Warm Atlantic Ocean waters are adding to Florence's strength, and computer models predict that the storm will make landfall Thursday in North Carolina or South Carolina as a major hurricane. Its impacts may be felt much deeper in the US, including in most of Virginia.

"Today is the day to get prepared all along the East Coast!" the National Weather Service tweeted on Monday morning. "Don't get complacent just because you live inland! Florence is forecast to bring devastating rainfall and flooding from the coast to the Appalachians."

In addition, the National Hurricane Center said that it will likely issue watches for "life-threatening storm surge" across three states.

Hurricane Helene

Arnold didn't photograph hurricane Helene, but said he saw its outer bands. Helene is a Category 2 hurricane that's blowing winds between 96-110 mph. The storm may turn northward in the coming days and bring a storm surge of up to 8 feet.

Any of these storms could strengthen into more powerful cyclones in the coming days.

Stay updated on our Hurricane Florence coverage here, and please prepare yourself now if any of these storms threaten an area where you live.

This story has been updated with new information.

Correction: A previous version of this story misidentified a photo of hurricane Florence as one of hurricane Helene; astronaut Ricky Arnold did not share a photo of the latter storm on Twitter.